Recent Advances in Organoactinide Chemistry As Exemplified by Cyclopentadienyl Compounds

The ubiquity of the cyclopentadienyl ligand permits us to use its complexes as representative examples for the description of recent highlights in organometallic and more generally in coordination chemistry of the actinides. Uranium(III) complexes exhibit a remarkable reactivity, especially in the activation of small molecules, and are valuable precursors of higher valent derivatives. Using redox-active ligands led to the design of reactive complexes which have been considered as synthons of An(II) and An(III) (An = Th, U). Studies of low-valent compounds gave a better insight into lanthanide(III)/actinide(III) differentiation. Organoactinide(IV) complexes with the bis-Cp* platform play a major role in the synthesis of a variety of compounds containing single and double metal-ligand bonds, revealing novel structures and reactions. The bis(cyclopentadienyl) uranium(IV) and thorium(IV) complexes were also found to be quite efficient in catalytic processes. Cyclopentadienyl complexes afford systems in which actinide ions potentially engage in magnetic exchange interactions. Organoactinide complexes in the +5 and +6 oxidation states remain relatively rare, and most of these are cyclopentadienyl derivatives with oxo and imido ligands.